When Apple brought out the current version of OS X, Snow Leopard, the changes were largely behind the scenes, and the most notable feature added was Microsoft Exchange support being integrated directly in the operating system. With Lion, most of the changes are upfront where users are better able to appreciate them. There are many new features, and the UI has been revamped.

One of the hallmarks of Lion is how Apple delivers evolutionary change that adds up to a revolutionary experience. It has taken many cues from iOS, the operating system used on the iPhone and iPad. Users of those two popular devices will feel very much at home with Lion. In fact, if you're partial to swiping to scroll and pinching to zoom in but you're a Mac desktop user, you might want to invest in an Apple Magic Trackpad to get the full Lion experience. Meanwhile, notebook users will discover that their trackpads have taken on new functionality.

One thing borrowed from iOS is a feature called LaunchPad. You can still keep much-used applications in your Dock, but LaunchPad will also display them using your full screen, just like the iOS home screen. (If they all don't fit, you just swipe right or left to see more.) Also as with iOS, you can group related applications together in folders. Of course, Apple doesn't give you the entire iOS experience, since its PCs aren't equipped with touch screens, but it is adapting to the way users have come to expect to interact with mobile devices and brought that to the large screen.

In another major UI shift, Apple has unified two technologies called Spaces and Expose. In previous versions of OS X, Spaces let users create virtual screens that could hold different applications for distinct tasks. Expose was a quick way of seeing all the applications running. Lion integrates these functions into a single tool that's accessed with one gesture. It's an example of Apple preserving the core user experience while refining existing features. You get a new experience without an offputting learning curve. I think a lot of people will appreciate that kind of gentle nudging along to the next thing, and it stands in sharp contrast to what many considered traumatic changes to Windows. (Ribbon, anyone?)

Microsoft also comes to mind when thinking about Apple's restraint in consolidating the functionality of its mobile and desktop operating systems. Apple has brought over to Lion from iOS only what makes sense for use on a PC. Microsoft keeps making the mistake of trying to replicate all behaviors across devices.

Of course, there's a lot more to Lion than what was borrowed from iOS. Other notable features include Auto Save and Versions for files. I've long argued that we must get past the need to use a save command. This vestigial remnant of the early days of computing has caused more than one user to lose hours of work as penalty for not saving often enough. Next thing you know, the power fails or you inadvertently close an application thinking your work has been saved. Auto Save eliminates that problem, and it also helps make Versions a great new feature. With Versions, you can "go back in time" (à la Time Machine) to see older versions of any document. Well, any document created with an application that supports Versions. Here's hoping developers get on board quickly to give us plenty of those.

Apple's core apps such as iCal have all been updated to support full-screen use. That includes Facetime video chat, which has also been integrated directly into the operating system. Of all the apps, Mail has gotten the biggest overhaul, with a new UI (that again takes many design cues from iOS), support for better searching and tagging of mail, and a more integrated view of threaded messages.

Boot times for Lion were quick, and system sleep and resume worked flawlessly on the Macbooks I tested it with. Applications now resume exactly where you left them, even after quitting them and shutting down, right down to the cursor location.

The decision to upgrade to Lion will be simple for most users. Unlike past operating system releases, which went for around $129, Apple is following the model introduced with Snow Leopard, selling an update online for $29.99. That price makes it pretty easy to justify the upgrade. Although Lion won't be available on an optical disk, Apple has backed away from its earlier announcement that it would be available only as a download from the Mac App Store. The company said today that, starting next month, it will sell a USB flash drive containing the Lion installer for $69.99.

Does it need to be said that, as much as I appreciate what Apple has done with Lion, I don't expect Microsoft to be surrendering its huge market-share advantage anytime soon? Nonetheless, Lion will only contribute to Apple's expanding mind-share. And little by little, that mind-share will have an effect even on companies' decisions about operating system deployment. IT is learning to listen to users (that's the only reason the iPhone has been able to enter so many enterprises), and increasingly, mind-share does indeed lead to market share.

Michael Gartenberg is a research director at Gartner. The opinions expressed are his own. Follow him on Twitter @Gartenberg.